Zirconium phosphate is a common material used in sorbent cartridges for sorbent dialysis. Zirconium phosphate can remove ammonium ions from spent dialysate, generated by the breakdown of urea in the spent dialysate by urease, as well as potassium, calcium, and magnesium ions from spent dialysate. Known sorbent dialysis systems do not provide for a way to recharge the zirconium phosphate present in a sorbent cartridge so that the zirconium phosphate can be reused for future dialysis sessions. Instead, known sorbent dialysis systems generally require the sorbent materials to be discarded and the sorbent cartridge replaced after each use. The discarding and replacement of expensive sorbent materials, such as zirconium phosphate, increases both costs and waste.
Zirconium phosphate operates by exchanging sodium and/or hydrogen ions bound to the zirconium phosphate for ammonium, potassium, calcium, magnesium and other cations present in spent dialysate. The ratio of sodium to hydrogen ions released by the zirconium phosphate into the dialysate may depend on the ratio originally bound to the zirconium phosphate. Known systems do not provide for a method whereby the ratio of sodium to hydrogen ions bound to the zirconium phosphate can be varied depending on the particular needs of each patient. Known sorbent dialysis systems do not involve the use of separate modules for the purpose of separating rechargeable sorbent materials, such as zirconium phosphate, from non-rechargeable materials, such as urease.
As such, there is a need for systems and methods for recharging sorbent materials such as zirconium phosphate for reuse. There is also a need for methods and systems for separating sorbent materials within a sorbent cartridge into single and multi-use modules that can facilitate recharging and reuse of at least one of the sorbent materials. There is further a need for systems and related methods whereby rechargeable sorbent materials can be separated into multi-use modules and single-use modules wherein non-rechargeable sorbent materials can optionally be contained in the single-use modules. There is also a need for a method of controlling the ratio of sodium to hydrogen ions bound to the zirconium phosphate, and changing the ratio based on physiological parameters obtained from a patient.